This application generally relates to design and production of custom printheads (e.g., side firing printheads). In one embodiment, printheads are fabricated by stacking slices, wherein the stack is held together via steel bracketing. It is to be appreciated, however, that the present exemplary embodiment is also amenable to other like applications.
In computing applications, there is a ubiquitous need to render electronic information into a tangible format. In such instances, a peripheral, such as a printer, can be employed to accept data from a computer, process the data and output the data as text and/or images onto a hardcopy substrate. A plurality of peripheral types can be employed to produce such hardcopy output including toner-based printers, solid ink printers, dye-sublimation printers, inkless printers and liquid inkjet printers.
Liquid inkjet printers operate by propelling variably-sized droplets of liquid or molten material (e.g., ink) onto a substrate. The inkjet printhead within the printer places droplets onto the substrate in one of three ways, via thermal, continuous and piezoelectric printhead cartridges. A thermal print cartridge utilizes a series of tiny electrically heated chambers, wherein a pulse of current through the heating elements causes a steam explosion in the chamber to form a bubble, which propels a droplet of ink onto the paper. Continuous inkjet cartridges utilize a high-pressure pump to direct liquid ink from a reservoir through a gun body, wherein a microscopic outlet creates a continuous stream of ink droplets. Piezoelectric cartridges use a piezoelectric material in an ink-filled chamber behind each outlet instead of a heating element. When a voltage is applied, the piezoelectric material changes shape or size, which generates a pressure pulse in the fluid forcing a droplet of ink from the outlet.
Piezoelectric inkjet technology is often used for marking in a manufacturing environment wherein the printhead is stationary as products move past it. Such print applications can require placement of information on a relatively precise location with an ever-decreasing size footprint. Information is rendered in hard copy format via placement of pixels in particular locations to create bar codes, text and/or images. To allow precise pixel placement, printheads are continuously designed and manufactured to emit ink from sub-micron sized apertures that are densely placed. Such inkjet printheads can be produced with modules arranged in a planar or stacked fashion, to maintain permissible dimensions and the packing density that can thereby be achieved to minimize manufacturing costs. In this design, slices of material (e.g., steel or other metal) are stacked wherein each slice performs a specific function.
In one example, some slices have cutouts to allow ink to be emitted from a plurality of predetermined locations. Other slices can contain piezoelectric circuits that control the delivery of ink to such apertures via one or several channels. Attention to precise adjustment is required to connect channels used to deliver ink through a number of modules. In addition, connecting channels of different lengths can require additional electronic control measures that can displace channels and/or change dimensional requirements for other components disposed within each layer.
Conventional designs of a stacked edge shooter printhead, such as those described in U.S. Pat. No. 5,850,240 (assigned to Francotyp-Postalia GmbH and incorporated herein by reference) can have many inadequacies that severely limit their use. For example, conventional designs are generally restricted to a resolution of 200 dpi that can be unsuitable for high resolution applications. Additionally, conventional printheads are designed for use at room temperature and thus can only be used with liquid ink systems. Moreover, conventional designs are limited to a small print width (e.g., one inch) that may obviate their use.
In addition, when an individual module malfunctions in a conventional stacked printhead, complicated assembly and adjustment can preclude its individual replacement and, consequently, a replacement of a complete inkjet printhead can be required. Due to the large number of outlets, these heads are significantly more expensive than inkjet printheads for standard office printers. Moreover, as size constraints increase, new design layouts can be required to meet specific print specifications. The generation of new printhead designs, however, can require a development cycle of two to three years or more.
To reduce this generational cycle and maintain stringent manufacturing standards, systems and methods are needed that utilize more standardized high-precision design paradigms.